My kids hate math repetition as well. It turns their favourite subject into dreary drudgery. Can your son be given 3rd grade math material? I'd definitely ask for this.

Also, imho, counseling never hurts. We've done private as well as in-school counselors. The intensity is just something you learn to live with, and it does ease up a little as they get older and more discerning as to what they respond to.